Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), yet the description adds substantial context beyond them: hand-curated provenance with official page and check date, a `confidence: "secondary"` marker for unverified rows, the ranking order, time-bounded rule caveats (Canada 2027, Australia March 2027, Saudi Arabia Jan 2026), and a mandatory not-legal-advice preamble. This is rich disclosure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One dense paragraph, but front-loaded with the core output list before caveats. The em-dash chains make it somewhat run-on; splitting the provenance/disclaimer tail from the mode-selection content would improve scanability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need no prose, and the description still supplies mode selection, ranking logic, provenance semantics, and temporal caveats. Nothing an agent needs to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3; the description exceeds it by defining the default ordering when no selector is passed, stating that `band` restricts the ranking, and clarifying that `countries` requires two or more for a side-by-side.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a precise verb+resource (whether a foreigner may buy residential property) and enumerates exactly what each row returns: ownership band, restrictions, land ownership, transfer tax, plus provenance. The band vocabulary is spelled out (`free`, `restricted`, `leasehold-only`, `prohibited`), so an agent can distinguish it from siblings like compare_housing or country_dossier.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly maps parameter combinations to behavior: `country` for one entry, `countries` for a side-by-side, neither for all 41 ranked free-first then by transfer tax, optionally narrowed by `band`. It does not name a sibling alternative it should be preferred over, which is the only gap.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.